The present invention relates to method for drilling and, in particular, impact drilling or rotary percussion drilling holes in soil or rock material, wherein a drill hole is formed by means of a drill bit mounted on a drill rod assembly and being forced by the drill rod assembly and being non-positively coupled therewith and a jacket tube surrounding the drill rod assembly in a spaced-apart manner and being introduced by the drill bit preferably by tensile action is introduced simultaneously. Furthermore, the present invention relates to a device for drilling and, in particular, impact drilling or rotary percussion drilling holes in soil or rock material and forming an anchorage, wherein a drill bit mounted on a drill rod assembly and being forced by the drill rod assembly and being non-positively coupled therewith forms a drill hole and a jacket tube surrounding the drill rod assembly in a spaced-apart manner and following upon the drill bit and being introduced by the drill bit preferably by tensile action is provided.
For the production of drill holes and the subsequent provision of an anchorage, methods and devices are known in which a drill hole is made by drilling and, in particular, impact drilling or rotary percussion drilling by means of a drill bit mounted on a drill rod assembly and, usually after the at least partial removal of the drill bit from the drill hole and the insertion of a roof bolt and injection of a hardening suspension such as, for instance, a concrete mix in the jacket tube remaining in the drill hole roof bolts may be set and anchored in soil or rock material. The drill rod assembly usually is designed to be hollow as may be taken, for instance, from AT-B 390 303, in order to enable a flushing agent to be supplied into the region of the drill bit for flushing and cooling the same, the worked material usually being conveyed outwards on the external periphery of the drill rod assembly. A jacket tube following upon the drill bit is introduced into the drill hole simultaneously with the drilling procedure in order to prevent the surrounding material from breaking in and thus filling up the drill hole, in particular, in case of loose rocks, thereby creating a defined clearance zone for discharging the worked material optionally together with the flushing agent. After completion of the drill hole the jacket tube remains within the same, thus accordingly facilitating the setting of a roof bolt into the drill hole and the subsequent filling with concrete. It is, however, immediately apparent that the removal of the drill bit together with the drill rod assembly involves a lot of time. Furthermore, the introduction of the flushing agent and the removal of the flushing agent together with the material to be worked call for an accordingly large inner cross section between the drill rod assembly and the jacket tube in order to enable such a removal. Moreover, it is to be anticipated that, when using a jacket tube remaining in the drill hole, only parts of the drill bit can be extracted from the completed drill hole, to which end a complex and, most frequently, multipart drill bit structure must be provided in order to enable the partial removal of the same along with the drill rod assembly. Furthermore, the removal of the drill bit and the subsequent setting of a roof bolt as well as the subsequent filling with concrete may possibly involve difficulties, in particular with great drilling lengths, if the jacket tube is damaged or, for instance, bent or buckled during the drilling procedure and hence the full cross section of the drill hole may no longer be available for removing the drill bit and setting the roof bolt.
Moreover, there has for example become known from DE-A 40 36 721 a method and a device for introducing rods or tubes into soils or walls wherein via an outer driving rod the impact and drilling energy being necessary for forming a drill hole is introduced into a drill bit and wherein the drill bit is coupled with a bar in the interior of the impact tube. After finishing the drill hole the impact tube being freely supported on the drill bit is removed, whereafter by introducing a hardening suspension a fixation and anchoring of the bar being attached to the drill bit takes place in the grounding material after hardening of the suspension.